Soap-detergent tablets

ABSTRACT

Personal washing tablets consisting essentially of a soap and an alkali metal or alkaline earth metal sulfate of a primary alcohol 10-75 percent of the molecules of said alcohol being branched, and wherein the soap content is 90-40 percent by weight of the combined contents of the soap and the sulfate.

United States Patent Inventors Allan Alsbury;

Dennis Parker Barrett, both of Win- England App]. No. 771,613

Filed Oct. 29, 1968 Patented Dec. 7, 1971 Assignee Lever BrothersCompany New York, NY.

Priority Nov. 16, 1967 Great Britain 52,254/67 SOAP-DETERGENT TABLETS 7Claims, No Drawings US. Cl 252/121, 252/132, 252/161, 252/DlG. 16 Int.Cl Clld l/l4, Cl ld 9/32, Cl ld 9/48 Field of Search 252/1 17,

Neodol Surfactants" published by Shell Chemical Company, 1967, page 5.

Primary Examiner-Herbert B. Guynn Assistant Examiner-Dennis L. AlbrechtAllorne vL0uis F. Kline, Jr.

ABSTRACT: Personal washing tablets consisting essentially of a soap andan alkali metal or alkaline earth metal sulfate ofa primary alcohol10-75 percent of the molecules of said alcohol being branched, andwherein the soap content is 90-40 percent by weight of the combinedcontents of the soap and the sulfate.

SOAP-DETERGENT TABLETS This invention relates to soap tablets whichinclude a synthetic detergent.

Tablets made from soap alone suffer from the disadvantages of inadequatelather produced in personal washing, and in the formation of curdy scumin hard water, i.e. water containing calcium and/or magnesium ions,which leaves an objectionable deposit on handbowls and baths (bathtubring).

Toilet bars made from synthetic detergents, whilst giving an acceptablevolume of lather, generally yield a lather having an open, noncreamystructure, unlike that from soap and not as acceptable generally to theuser of the bar for personal washing. The rates of wear in use ofsynthetic detergent bars tend to be much higher than those of soaps.Many synthetic detergents, however, have the advantage that they do notproduce the objectionable scum that is characteristic of soaps.

It is also known that many synthetic detergents are incompatible withsoap, in that their lathering actions are mutually destructive.

It has now been found that blends of soaps with the alkalimetal oralkaline earth salts of the sulfates of certain synthetic alcohols arenot only compatible, as regards lathering properties, but that thelather volume produced is unexpectedly high. The unexpectedly highlather volumes are now found to accrue from tablets wherein the soap andsulfate are present within critical limits. The quality of the lather,i.e. its closeness and creaminess, is good. In these blends the scumformation characteristic of the soap element is suppressed oreliminated. Furthermore these advantages are achieved whilst maintaininga user-acceptable rate of wear of the bar in use.

The present invention is concerned with a toilet table which comprises asoap and an alkali metal or alkaline earth metal sulfate of a primaryalcohol, 10-75 percent of the molecules of said alcohol having theformula wherein n is an integer from 7-14, R is a substituent which isan aliphatic radical having one-four carbon atoms, and the number ofcarbon atoms totals l [-1 8, in which the soap content is 90-40 percentby weight of the combined contents of the soap and the sulfate.

The sulfate will be referred to hereafter as the branched chain alkylsulfate." Suitable alkali metals are sodium and potassium, and suitablealkaline earth metals are calcium and magnesium.

The preferred primary alcohols are those branched per 100 molecules ofalcohol, to the extent of 50-90 molecules unbranched, 10-50 moleculeshaving R as methyl, -10 molecules having R as ethyl, and 0-15 moleculeshaving R as an alkyl radical of three or four carbon atoms.

Preferably, the branched chain alkyl sulfate is one which is made bysulfation of alcohols having l2-l5 carbon atoms. Preferably thesubstituent R is methyl, and the cation is preferably sodium.

The unexpectedly high lather volume values accrue from tablets whereinthe branched chain alkyl sulfate lies within the range of about 10 toabout 60 percent by weight of active detergent material, i.e. soap plusbranched chain alkyl sulfate. That is, a 60:40 mixture of sulfatezsoaprepresents the terminal region at which the unexpectedly high lathervolume is obtained. Although with some blends of soap and branched chainalkyl sulfates, where the amount of sulfate is at the lower end of therange of the invention, the rate of wear of the tablets, whilst beinguser acceptable, is as expected from the composition. Further, when thelarger amounts of the branched chain alkyl sulfate within the range ofthe invention are used, it has surprisingly been found that the rate ofwear does not increase further, but in fact is less than expected fromthe composition of the tablet.

The preferred ratios of soap to branched chain alkyl sulfate lie withinthe range 5:] to 3:2. When the degree of branching in the branched chainalkyl sulfate is low at the percent level of branching, then the amountof the sulfate required is of the order of 45 percent, and when thebranching is higher, at say 40 percent, then the amount of the sulfateneeded is of the order of 25 percent. Generally, the preferred amount ofbranched chain alkyl sulfate is about 30 percent by weight of soap plusthe alkyl sulfate.

The preferred sulfates may be made from the alcohols which arecommercially known as Dobanols (Shell Chemical Co. RTM) in the UK andNeodols in the USA. These alcohols include both odd and even numberedcarbon chains in the range of 12-15 carbon atoms are branched to theextent of 25 percent; it is believed that 25 percent branching isZ-methyl.

The sulfation of these alcohols and the subsequent neutralization may becarried out by methods using a sulfating agent such as SO /air,chlorosulphonic acid etc., for example in a stirred tank, or in afalling film reactor. The product of sulfation is neutralized preferablyby aqueous caustic soda. It has been found that the resultantneutralized paste can then be coprocessed with the soap-stock by thenormal soap processing techniques of drying, milling, plodding andstamping to yield firm bars of excellent surface finish.

The soap component of the tablets may be selected from a wide range offat-charges as is familiar in the soapmaker's art. For example it may bederived entirely from tallow, i.e. the natural fat in which the fattyacid distribution is generally understood to be mainly 30 percent C and20 percent C saturated with 42 percent C unsaturated. In place oftallow, various oils and fats commonly used in soap-making may be used,for example, bone-grease, Chinese vegetable tallow, cottonseed oil,partially hydrogenated groundnut oil, lard, palm oil, or whale oils.

Or it may be a blend derived from tallow with a nut oil, for examplepalm kernel or coconut oil. Typically, the fatty acid distribution innut-oils is 45 percent C 14 percent C and 10 percent C saturated and 20percent C unsaturated. The soap may also contain 10-20 percent of afatty acid derived from a soft oil i.e. ground-nut oil. The blend oftallow and nut oil soaps may be in the ratios commonly used in toiletsoaps, for example in the UK such ratios could be :20, 50:50, 40:60, or35:65. The higher nut oil concentrations are not commonly usedelsewhere. Soaps derived from synthetic fatty acids of similar chainlength distribution may be used.

The soap base may, optionally be superfatted, for example by theaddition of free fatty acids. This is a common practice in soap toiletbars as a method of achieving an increased creamy fee] which isconsidered desirable from a consumers viewpoint. The amount ofsuperfatting agent is generally about 10 to 20 percent based on the soappresent, but may be up to 30 percent, or even 50 percent based on thesoap content, in the tablets of the invention which have the lower soapcontent. Where the superfatting agent is chosen to be a free fatty acid,this may be liberated in situ by the addition of certain mineral ororganic acids e.g. phosphoric acid or lactic acid. However, the fattyacid or other selected superfatting agent may have the same or differentcarbon chain distribution from that of the soap component.

The invention will now be described by way of examples in which thebranched chain alkyl sulfates are derived from the Dobanol (Neodol)alcohols designated 45, 23 and 25, i.e. blends having carbon chainlengths ofC and C C and C and C C, C and C respectively, and are thesodium salts.

In the following examples the figures in brackets represent respectivelythe expected levels of lather volume, and rate of wear i.e. the volumeor rate of wear calculated from a linear relationship drawn between thevolumes or rates of wear obtained for a bar whose active consists ofpercent specified soap and a bar whose active consists of 100 percentspecified alkyl sulfate.

The methods used to obtain the results quoted in the examples aredetailed later. All percentage compositions are on a dry weight basis.

EXAMPLE 1 Toilet bars were prepared by normal soap processing techniquesto the compositions in the following table.

The soap used consisted of the sodium salts of the fatty acids derivedfrom toilet grade tallow.

Percentage composition Lather Rate of wear Mush, volume (machine wt.Total Dobano146, at 20 C. test) at 20 loss mush Soap sulphate (mls.) C.gms. (gms) (gins) Synergistic lather volume is shown by compositionscontaining 20, 40 and 60 percent of the branched chain alkyl sulfate,whilst negligible changes in rates of wear and mushing tendencies areeffected (negligible change is one which is insufficient to beappreciated by a user).

EXAMPLE 2 Toilet tablets containing sodium soap derived from the fattyacids of tallow and palm kernel oil in the ratio of 4:1 and Dobanol 45sulfate were prepared according to the composition given below.

Percentage composition Lather Rate of wear Mush, volume (machine wtTotal Dobanol45, at 20 C. test) at 20 loss mush Soap sulphate (mls.) C.gms. (gms (gms.)

The lather volumes of blends containing 20 and 40 percent Dobanol 45sulfate are higher than anticipated from their compositions. Althoughthey contain the readily soluble alkyl sulfate, the rates of wear andmoshing tendencies are surprisingly little affected.

EXAMPLE 3 Toilet bars were made from soap consisting of the sodium saltsof the fatty acids derived from tallow and palm kernel oils in the ratioof 3:2, with 10 percent by weight of fatty acids of the same compositionas superfatting agents, and Dobanol 45 sulfate, as shown in the table.

Percentage Composition Lather volume Soap Dobanol 45 C. 40 C.

sulfate Synergistic lather volume production is shown by these examples.

EXAMPLE 4 Toilet bars were prepared, by normal soap processingtechniques, to the composition shown in the following table.

The soap used in the example comprises the sodium salts of equal partsof the carboxylic acids derived from tallow and coconut oil, with 10percent by weight of added free fatty acids of the same composition.

The sodium salt of the sulfate obtained from Dobanol 45 was used.

Ratc-of-wear Percentage composition Lather volume (mls.) (machine test)gins.

Soap sulphate 20 C. 40 C. 20 C. 35 C.

These data show the marked synergism in lather volume by thecompositions of the invention.

EXAMPLE 5 The invention is similarly exemplified when the sodium salt ofthe sulfate derived from Dobanol 23 is used in the same superfatted soapblend as used in example 4.

ll COmPOSlU'OH Lather volume Rate of Wear Soap Dobanol 23 at 20 C (ml(Hand washing sulfate test) at 20 C. gms.

Synergism in lather volume is demonstrated by the composition accordingto the present invention. This example also shows that when a higheramount of the branched chain alkyl sulfate is used, only the expectedlather volume is obtained, and there is a considerable increase in rateof wear over the composition in the preferred range.

EXAMPLE 6 The invention can be further exemplified when Dobanol 25sulfate is incorporated in toilet bars containing a superfatted soapbase consisting of equal parts of the sodium salt of the fatty acidsderived from tallow and coconut oil together with 10 percent by weightof the free fatty acids.

Percentage Composition Lather volume Toilet bars containing soapsconsisting of the sodium salts of the fatty acids derived from tallowand palm kernel oil in the ratio of 2:3, and 20 percent Dobanol 45sulfate were made. Similar bars were also made containing 10 and 20percent by weight of fatty acids of the same composition as superfattingagent.

Percentage Composition Lather volumes at 20 C. Soap alone 369 Soap plus10% superfat 749 Soap plus 10% superfat plus 20% Dobanol 45 sulfate 394(748) Soap plus 20% superfat 674 Soap plus 20% superfat plus 20% Dobanol45 sulfate 836 (688) Soap plus 20% Dobanol 45 sulfate 695 (443) Dobanolsulfate alone 739 These data demonstrate that synergism in lather volumeis present when soap/branched chain alkyl sulfate blends are used aloneor with 10 and 20 percent fatty acids as superfatting agent.

EXAMPLE 8 Toilet bars have been made containing a :superfatted soap baseconsisting of the sodium salts of the fatty acids derived from tallowand coconut oils in the ratio of 7:13 together with 10 percent by weightof the free fatty acids, and Dobanol 45 sulfate in the proportionsindicated in the table below.

The synergistic lathering action of compositions within the invention isdemonstrated, as in the nonadverse effect on the rate of wear andmushing tendencies.

EXAMPLE 9 Toilet bars have been made containing the superfatted soapbase as described in example 8 and Dobanol 25 sulfate in the proportionsindicated in the table below.

Percentagecompositlon Lather Rateolwear Mush, volume (machine wt TotalDobanol45, at 20 0. test) at 20 loss mush Soap sulphate (m1s.) C. gms.(gms.) (gms.)

The synergistic lathering action of compositions within the invention isdemonstrated, as is the nonadverse effect on rate ofwear and mushingtendencies.

it will be appreciated that the tablets of the present invention mayinclude coloring agents, perfumes, germicides, bacteriostats, or agentsfor improving the characteristics of feel. These agents are well knownin the art.

TEST METHODS Lather Volume Test The tablet is conditioned by use innormal washing once or twice to produce an in-use" rather than freshsurface. This ensures that the surface is the same at the beginning asat the end of the test.

The operator uses 2% liters of water at the desired temperature (usually20 C. or 40 C.) in a hand bowl. Surgical quality rubber gloves are wornto obviate the variable effects of sebum from the skin, withoutdestroying the sensitivity of the operation. The gloved hands and thetable are dipped into the water, removed and the tablet twisted 15 timesin the hands as in normal washing, then placed on a drained dish. Thehands are rubbed together, palm to palm 10 times, then each hand twistedin the other, alternately 10 times. The rubbing and twisting sequence isrepeated and the lather so formed collected in a measuring cylinder.

The sequence of operations from the twists of the tablet is repeatedtwice more and the total volume of lather from the three latheringsmeasured.

Tests are performed, desirably in duplicate.

Rate of Wear-Hand Washing Test A panel of six testers working inrotation washes down each tablet 6 times per day for 4 days. Eachwash-down consists of 40 twists, a twist being defined as a rotation ofthe tablet through 180 in the hands. Two conditions are normally usedfor the test; tablets are washed-down in water (a) at 20 C. and (b) at40 C. and kept on drained dishes between wash-downs.

The tablets are then air dried to constant weight (usually for 5 days),and the rate of wear results are given as the dry weight loss in grams."

Tablets of the same size and shape are used, otherwise it is necessaryto adjust the weight losses for tablets of difierent surface areas.

Rate of WearMachine Test Bars of test material are subjected tocontrolled mechanical abrasion under fixed conditions of time, load andintermittent wetting at a chosen, controlled temperature. The weightlosses, after drying, are sensibly related to those occurring in normaluse.

MUSH

The weighed (W tablets, as rectangular blocks, are suspended in about100 ml. of water at 20 C. for 2 hours, so that a known surface area (A)is immersed. On removal, the tablet is reweighed (W,,,). The mush isremoved with a straight edge (e.g. a polythene scraper), the tabletgently wiped free from mush with a tissue and, after drying in airovernight, reweighed (W,);

I Weight 1oss= per 50 sq. om.

Total mush= fi per 50 sq. cm.

What is claimed is:

l. A toilet table having synergistic lather volume essentially of a. asodium soap selected from the group consisting of sodium tallow soap andmixtures of sodium tallow soap with sodium palm kernel oil soap or withsodium coconut oil soap in the weight ratio of from :20 to 35:65, and

b. a sodium sulfate salt of mixed C to C linear primary alkanols, about25 percent of which molecules have a 2- methyl branch chain; the weightratio ofsoap to sulfate being from 80:20 to 40:60.

2. The toilet tablet as defined by claim 1 which further contains aboutlO-20 percent by weight of the soap of a free fatty acid superfattingagent derived from said soap.

3. The toilet as defined by claim 1 wherein component (a) is sodiumtallow soap, and component (b) is the sodium sulfate salt of mixed C toC linear primary alkanols, about 25 percent of which molecules have a2-methyl branch chain; the weight ratio of soap to sulfate being about40:60.

4. The toilet tablet as defined by claim 1 wherein component (a) is amixture of sodium tallow soap with sodium palm kernel oil soap in theweight ratio of about 80:20, and component (b) is the sodium sulfatesalt of mixed C, to C linear primary alkanols, about 25 percent of whichmolecules have a 2-methyl branch chain; the weight ratio of soap tosulfate being about 60:40.

5. The toilet table as defined by claim 2 wherein component (a) is amixture ofsodium tallow soap with sodium coconut oil soap in the weightratio of about 35:65, and component (b) is the sodium sulfate salt ofmixed C to C linear primary alkanols, about 25 percent of whichmolecules have a 2-methyl branch chain; the weight ratio of soap tosulfate being about 70:30; said toilet tablet further containing about10 percent by weight of the soap of a free fatty acid superfatting agentderived from said soap.

6. The toilet tablet as defined by claim 5 wherein the weight ratio ofsoap to sulfate is about 60:40.

consisting 7. The toilet tablet as defined by claim wherein the weightratio of soap to sulfate is about 50:50.

2. The toilet tablet as defined by claim 1 which further contains about10-20 percent by weight of the soap of a free fatty acid superfattingagent derived from said soap.
 3. The toilet as defined by claim 1wherein component (a) is sodium tallow soap, and component (b) is thesodium sulfate salt of mixed C14 to C15 linear primary alkanols, about25 percent of which molecules have a 2-methyl branch chain; the weightratio of soap to sulfate being about 40:60.
 4. The toilet tablet asdefined by claim 1 wherein component (a) is a mixture of sodium tallowsoap with sodium palm kernel oil soap in the weight ratio of about80:20, and component (b) is the sodium sulfate salt of mixed C14 to C15linear primary alkanols, about 25 percent of which molecules have a2-methyl branch chain; the weight ratio of soap to sulfate being about60:40.
 5. The toilet table as defined by claim 2 wherein component (a)is a mixture of sodium tallow soap with sodium coconut oil soap in theweight ratio of about 35:65, and component (b) is the sodium sulfatesalt of mixed C14 to C15 linear primary alkanols, about 25 percent ofwhich molecules have a 2-methyl branch chain; the weight ratio of soapto sulfate being about 70:30; said toilet tablet further containingabout 10 percent by weight of the soap of a free fatty acid superfattingagent derived from said soap.
 6. The toilet tablet as defined by claim 5wherein the weight ratio of soap to sulfate is about 60:40.
 7. Thetoilet tablet as defined by claim 5 wherein the weight ratio of soap tosulfate is about 50:50.